Up till now I have only printed single-nozzle models, thus with support in the same material as the part, and with older Cura-versions. So I can't really say what is going on here, or what the best option is.
If I had to print it for myself, and if the model and function would allow it, I would redesign it slightly, so it can be printed without supports. By adding 45° angles to the overhanging areas. And I would use a brim (or even custom designed brim) to keep it stable on the bed, to prevent it from being knocked over.
If redesigning would not be possible due to its functionality, I might consider designing custom supports, maybe a mix of free-hanging supports with an interface-layer of PVA? But I don't know if this would work, I never tried it. See the concepts below.
Concept of (almost) free-hanging supports:
As printed (the middle part of the bridge got similar almost free-hanging supports, but they are not shown in the CAD-model above):
After cleaning-up: there is very little damage to the side-walls due to the thin connection-strands, and of course no damage at all to the design at the bottom. For reference: all walls are 1mm thick here:
Concept sketch of basic support structure in PLA, with a dove-tail interface in PVA, so the bottom areas of the real model on top are kept clean. This would give a very stable support base, easy to print in cheap PLA (in case the model is PLA). The dove-tail is to have the support-interface in PVA stick very well to the PLA base. But as said: I don't know if this would work in reality, never tried it yet, but it seems like it should work. :-)
If you would consider these concepts, do tests on small dedicated test-models, so you don't waste too much time and material. Stay with the printer and watch closely how it prints.
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GregValiant 1,454
This is with a rectangular support blocker covering the threads.
Within my gray circled area the threads are being supported as evidenced by the support interface roof lines. I played with the settings and I could not eliminate this. The results were the same with a 34mm diameter x 12 cylinder and with a 34mm diameter x 195 cylinder. Switching from Tree to Normal supports made no difference, the threads were still being supported. Even with the support angle at 75° the threads were being supported and that should have been beyond the (I assume) 60° included angle of the thread form.
I've worked with models with similar features but I've never seen this problem. What Cad software was used to design this and how was the STL file generated? (There were a couple minor problems with the model but a repaired STL sliced exactly the same.)
Maybe @Torgeir, @geert_2, @nallath, @gr5 or one of the other more experienced people have a better take on what's going on. I hate being baffled before my second cup of coffee.
I'm still baffled. This is with a support blocker covering the entire model.
Here is the top layer. The support is not supporting anything, and the threads are still supported.
So I went back to the "repaired" model and tried again. I had been playing with the support settings for the un-repaired model when I brought the fixed model in. This time I went back to my defaults before bringing the fixed model in. I think it worked.
I have now set a personal record for most attachments to a post.
SlickUpper_fixed.3mf
Edited by GregValiantLink to post
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